Endoscopically Diagnosed Gastric Cancers: Looking Alike, but Behave Differently

cancer remains the second leading cause of cancer mortality in the world, although the overall incidence is gradually declining. 1 Gastric cancers can be largely subdivided into early and advanced lesions in nature or intestinal and diffuse type in pathology. Early gastric cancer (EGC) is defined as a cancer that does not invade beyond the submucosa regardless of lymph node involvement, based on which endoscopic resection for EGC has become an established alternative effective treatment method through improved technology alongside with instrumental development. 2 Endoscopic resec-tion for mucosal or minimal submucosal, small sized, and differentiated tumor is curative because lymph node metastases are rare in these tumors. 3 Of course, accurate staging especially prediction of the depth of tumor invasion is indispensable. On remote definition, the evaluation of depth of invasion was performed by gastroduodenoscopy based on the macroscopic appearance. Type 0 is superficial (T1, mucosal and submuco-sal invasion) tumors, and classified as EGC. Type 1 is polyp-oid tumors, type 2 is ulcerated tumors with raised margins surrounded by a thickened gastric wall with clear margins, type 3 is ulcerated tumors with raised margins surrounded by a thickened gastric wall without clear margins, type 4 tumors without marked ulceration or raised margins, the gastric wall is thickened and indurated and the margin is unclear, and type 5 is tumors that cannot be classified into any of the above types 4. Type 1 to 5 is classified as advanced gastric cancer (AGC). 4 With more detailed insights, type 0 was further classified into EGC as follows; EGC type I (elevated), EGC type II (flat, a, b, c), and EGC type III (excavated) based on endoscopic morphology by Japanese Society of Gastrointestinal Endoscopy. Since bare-eye gastroscopic classification was imposed for gastric cancer, the accuracy of preoperative diagnosis of EGCs is limited, 5.9% to 22.2% of cases of clinically diagnosed EGCs are actually AGCs. The endoscopic distinction between early and early-like advanced cancers was correctly made in 83.6% of the cases. 9 Misdiagnosed AGCs frequently have a macroscopic appearance like EGC, can be recognized as a subgroup of cancer, namely EGC-like AGC or AGC simulating EGCs. They showed different behavior as compared to conventional EGC or AGC. Most of these particular car-cinomas were of the depressed type and frequently related to ulcer on gross inspection. Histologically, the tumors were of diffuse type in 60%, and the rate of the carcinomas restricted to within …